<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .sliderbar {
      position: fixed;
      right: 0;
      bottom: 100px;
      width: 40px;
      height: 40px;
      text-align: center;
      line-height: 40px;
      cursor: pointer;
      color: #fff;
    }

    .con {
      position: absolute;
      left: 0;
      top: 0;
      width: 200px;
      height: 40px;
      background-color: purple;
      z-index: -1;
    }
  </style>
  <script src="animate.js"></script>
</head>
<body>
<div class="sliderbar">
  <span>←</span>
  <div class="con">问题反馈</div>
</div>
<script>
  var sliderBar = document.querySelector('.sliderbar');
  var con = document.querySelector('.con');

  sliderBar.addEventListener('mouseenter', function () {
    animate(con, -150, function () {
      sliderBar.children[0].innerHTML = '→';
    });
  })
  sliderBar.addEventListener('mouseleave', function () {
    animate(con, 0, function () {
      sliderBar.children[0].innerHTML = '←';
    });
  })
</script>
</body>
</html>